Animal clarity

Ages ago, I remember seeing a nature program about animal intelligence. Researchers had put a banana in the center of a clear tube, open at both ends, that was just past the reach of a monkey's arm. The aim was to see if the animal would use a tool to push or pull the fruit out. The monkeys wanted that banana, but none thought to use a stick to extend their reach. But one of them did have a bright idea. He snatched up a baby monkey, shoved it in the tube and pulled it back out, and then stole the banana that the little guy had retrieved! I couldn't find a clip of this, but did find mention of such an experiment and similar animal cognitive studies of monkeys.
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My memory had been sparked by a story in the scientific weird news about hermit crabs moving into hand-blown glass shells, which allows researchers at New Zealand's Marine Science Centre to visualize how they get in and out of their adopted homes and what they do in there, including aerate their eggs. I went in search of other animals in clear housing for purposes of scientific observation and found this National Geographic video of my old friend the octopus, demonstrating the flexibility it has without any bones or air bladders. This 600-pounder squeezes through a passageway the diameter of a quarter! The narrator asks, "Can you imagine how fun it would be to be an octopus?" Only on Halloween, my friend, only on Halloween...